


Snikt

by vericus



Series: Sparks AUs [1]
Category: Transformers (Bay Movies), Transformers - All Media Types
Genre: F/M, sticky smut, trucker cursing
Language: English
Status: Completed
Published: 2014-09-08
Updated: 2014-09-08
Packaged: 2018-02-16 14:13:17
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,954
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2272800
Author URL: https://archiveofourown.org/users/vericus/pseuds/vericus
Summary: <blockquote class="userstuff">
              <p>This is definitely what Ratchet meant when he told Optimus to 'stress test' his new upgrade, yeeeeeah...</p>
            </blockquote>





	Snikt

**Author's Note:**

> So, credit goes where it's due: there's dozens of other authors and fanfics out there that have given me the basic ideas for the mechanics of much of this fic, most notably _[A Dance to Remember](https://www.fanfiction.net/s/4016243/1/A-Dance-to-Remember)_. I'm hoping I'm not stealing too blatantly from anyone, but honestly I've read so much fic it gets all jumbled together, so tell me if I am.
> 
> I'd love to blame Caz for this, too, and take essentially no credit, but really this was the pairing Sparks was meant to have, until Optimus took things in a platonic direction instead. So uh. I dunno, guess I've gotta take the blame for finally writing it.
> 
> Also: while this is Sparks 'verse technically, no background knowledge beyond "Optimus has a sassy trucker charge who can talk to Autobots in her head" is required.

"Alright, we can go," Optimus said with full-blown fake casualness as he left the med bay. To his credit, he only took two steps before looking back to where his charge was standing by the med bay doors, arms crossed over her chest and giving him an unimpressed look.

"Ratchet and Wheeljack have been tied up with _whatever_ this was for _over a year_ , not even _Jazz_ will give me hints about what it is, and when they finished, you hauled _the Ark_ down from orbiting Jupiter, necessitating a fight over space travel technology with the government that you've been avoiding _since before I met you._ Then it turns out that whatever's going on, it requires you, Ratchet, and Wheeljack locking yourselves in a _Cybertronian_ med bay for _seventy-two hours_ , while I piddle around in butt-fuck-nowhere Wyoming because that's the only place you could get clearance to land your damn ship...and you expect to walk out of here with just an 'alright, we can go'?" The news stories always went on about how impressive, how imposing, even how utterly terrifying the alien leader of the Autobots was up close - and he was. But he still cringed at the tone his charge used, well aware of the fact that she'd repeatedly mentioned that she could remember rebuilding him, which meant she knew how to take him apart, too.

"I'll explain later?" the Prime offered, holding out a hand for her to climb into. She didn't need it - she was adept at climbing up his mechanoid form - but it was a courtesy thing at this point. The Autobots had initially been worried that the humans would take offence at the idea of being carried around, but it turned out that as long as they were offered a choice, the humans were more than happy to be carted around. Alex preferred it, in fact, and grew grumpy whenever a function was too 'formal' for her to ride around on Optimus's shoulder or hand.

"How much later?" Alex said after a moment of considering the offered hand.

"Tonight?" Optimus suggested. "Or possibly tomorrow, depending on if the road is blocked."

"Road? To where?" Alex demanded suspiciously. "I swear to god, if you're taking me _any further_ into _buttfuck nowhere_..."

"Alex, please, I'll explain everything within the next few days, but this is not a project we'd like spread around," Optimus said, sounding more than a little put-upon. Alex suspected Ratchet was listening through the med bay doors and laughing at the Prime over comms. Still, she scowled, well aware that he hadn't denied his intentions to take her even further from civilization. The Autobot _comm net_ was spotty for her out here, and that was saying something.

"Fine," she snapped at last, stepping over and climbing into his hand. "But you owe me for this. You owe me a _lot_ of something that I will figure out later."

"Of course," Optimus said mildly as he lifted her to his shoulder. Alex climbed up and settled herself into the little niche in his shoulder armor that everyone just ignored he'd formatted especially for her. It was a fairly common customization these days anyways - it was just that Optimus had done it first.

"I'm going to assume you've thought about things like food," Alex said evenly as Optimus headed towards the Ark's exit.

"We'll be making a stop at the camping store in town," the Prime said, looking straight ahead, and Alex's scowl returned full-force.

"Camping, Optimus?"

"Not for gear, simply supplies," he assured her, sighing. "There's a cabin at our destination."

"And you're sure it's not full of psychopathic murdering hillbillies?" Alex drawled. "Cuz cabins in the middle of buttfuck nowhere don't exactly have a good track record. Just sayin'."

"Ironhide had a look himself," Optimus said, reassuringly.

"Oh, so it comes with a giant robotic psychopathic murdering hillbilly," Alex deadpanned. Optimus shrugged his shoulder - no more than a minor inconvenience for Alex, her reflexes long honed enough to grab on without even needing to think about it - and gave her a tolerantly amused look.

"He looked and left. He's back in Nevada with Major Lennox now," he said.

"So since he's gone, the psychopathic murdering hillbilly could have -"

" _Alex_." The Prime gave her an exasperated look. "I will be _right there_ the _entire_ time."

"And if they kidnap me while you're recharging, drag me down into some top-secret -" Optimus cut her off by transforming, having reached the exit ramp for the Ark. Alex held her pose, letting him drop her into his driver's seat before continuing. "- torture dungeon embedded deep in the bedrock where you couldn't get to me without caving everything in?"

"You are impossible sometimes," Optimus told her, sighing as he pulled out, heading down to the logging road that was the only access to the Ark's landing site.

"Right back atcha," Alex said cheerfully. Optimus's response was to turn the radio on at a volume that precluded further conversation, and Alex snickered.

\---

Despite her clear displeasure with their continued journey deeper into Wyoming wilderness, Alex was a champ about getting supplies at the camping store. The clerk was nice enough, too, though he had that sort of sleazy feel to him that had Alex sure he was picturing her barefoot and pregnant in his kitchen the entire time she was in the store. She carried her things out with a shudder, piling them on the sleeper bunk before slipping the platinum credit card back into Optimus's visor. The government didn't know that particular card existed, nor the accounts connected to it - but in an economy where so many transactions were done electronically, it hadn't been hard for the Autobots to get themselves local currency, with certain bots playing the markets or gambling sites since their arrival to ensure the Autobots had a nice little nest-egg of money to fall back on when they didn't want the government to know about what they were doing. It was also helpful for spoiling or bribing their charges, something they did more often than any of them would like to admit.

Alex stayed in the driver's seat of Optimus's cab until they left town, and then decided there was little enough traffic to be freaked out by a driverless truck that she could unwrap and properly pack all of her new purchases. Optimus played some Elvis, and it was almost like any other haul as they both sang along badly with the King while Alex did things in the sleeper bunk. Eventually she had everything packed away in her two duffel bags and one travel cooler, though, and returned to the front seat. Her fingers drummed on the steering wheel as she looked around, falling silent, and the music turned down.

"You'll keep a sensor out for bears and cougars and shit, right?" Alex asked eventually, abruptly.

"Of course," Optimus said amiably, and kindly - wisely - did not mention the fact that her adrenalin was spiking as she shifted nervously in his seat. It seemed that after everything she'd gone through, Alex was actually scared of the wilderness of her own planet. Whether that was something purely her, or the result of her memories of how Cybertron Valley was created, Optimus couldn't say.

The drive took the remainder of the day, and they arrived at the cabin deep in Wyoming wilderness as the sun slipped behind the trees, casting everything in a spooky light. When Optimus turned off his engine, he realized Alex was gripping his steering wheel, staring somewhat blankly at the structurally sound, but clearly long abandoned, cabin in front of them.

"Yeah I'm sleeping in here tonight," she said after a long moment, clearing her throat.

"Alex, it's fine, there's nothing but birds around for miles," Optimus assured her. "And no blank spots on my sensors indicating any type of hidden facilities or rooms."

"But -" Alex paused. "No. No, I can do this. Totally. Just a cabin in the middle of the woods. No biggy, been through scarier shit." She pried her hands off Optimus's steering wheel, but didn't move any further.

"Didn't you want that explanation?" the Prime coaxed.

"Yeah," she said, taking a deep, shaky breath, and Optimus for the first time found himself actually worrying about this plan of action. He hadn't anticipated Alex actually being frightened by a cabin in the middle of nowhere. Then her next words came to him over the network, and though her signal was too weak to reach most of the other Autobots out here, she was inside him at the moment and he could hear her clearly. _"Dump me out. Only way I'm gonna get out."_

_"Alex, if you're truly frightened by this -"_

_"Dump. My ass. Out."_

Optimus opened his door and booted her out as requested, then transformed around her things. She grumbled and pushed herself up, dusting at her pants before glancing around, peering into the darkness.

 _"We can return to town if you wish,"_ Optimus said apologetically over the network, taking his cue from her.

 _"No, I'm sure you had your reasons, so let's just...get this over with. Hand me my stuff, I'll take it inside and light the place up, then we can talk,"_ she said, straightening her shoulders. She gave Optimus a determined look, and he couldn't help but smile as he once again saw the woman that had thrown rocks at Barricade within moments of finding out giant alien robots were real.

"I have a better idea, actually," Optimus said aloud, and transformed again. Being the first time he'd done this particular transformation without medical supervision, it took longer than normal, especially considering the complex pieces of technology - even for them - that were making the transformation even possible. It was a full minute before the last part slipped into place, and he flexed his limbs before turning his attention to Alex. She was staring with wide eyes and a slack jaw, completely flabbergasted. "Surprise?" Optimus offered with a small smile. Alex blinked a couple times.

"Da fuck?" she got out after a couple failed attempts to say anything else.

"It's something that Cybertronian scientists having been working on for decades, actually, but I'm told they didn't have the prerequisite technologies before the war, and since then none of them have had the time or inclination to pursue the subject - until recently, of course," Optimus supplied.

"Why?" Alex asked after a moment, looking puzzled.

"Why what?" Optimus asked, arching an optic ridge in amusement.

"There _are_ a lot of 'why' questions attached to that, aren't there?" Alex mused, then took a few steps forward. Almost tentatively, she reached out and gave him a solid shove in the shoulder. She seemed fascinated at the fact that she could actually move him now with such an action, and Optimus stood there, bemused, as she circled his now six-foot-high mechanoid form. Externally, it looked like almost an exact replica of his larger form, albeit simplified in places, lacking in all weaponry, and most of his armor. She waved her hands over his head and behind him, as if he was hiding the rest of his mass with a hologram, then peered into the cracks in some of his plating before inspecting his profile at close range - the need to protect much finer components had resulted in a one-piece faceplate that not only covered up the mechanical bits, but gave him a remarkably human-like face.

"I don't have the light I need to see this properly. I assume you don't still weigh the same?" Alex finally said.

"No, I don't, and Ironhide checked that the cabin was structurally sound enough to support my new weight," Optimus said with a small grin.

"Hmph. Fine. You can carry everything inside, then," Alex declared, heading for the cabin at a determined clip. Optimus chuckled and did as ordered, grabbing the cooler and two duffel bags before heading inside. Alex was looking around the mostly-empty room consideringly, though her gaze kept catching on the fireplace. "Did Ironhide check to see if the chimney was in working order?" Optimus paused and checked with his weapons specialist.

"He says it is."

"Great. Go get us some wood with your big-ass self," Alex said, grinning widely. "Shoulda bought that damn s'more kit, but oh well!"

"I'm fairly sure you need a permit to -"

"If you do not provide me with firewood, either from a deadfall or a freshly Prime-chopped tree, I am going to disassemble you in your recharge. And you're small enough now I could do it overnight," Alex told him sweetly.

"...I'll be back shortly," Optimus said, setting the bags down in the center of the cabin.

"And keep a damn sensor out for me the entire time, special-spark," Alex ordered as she immediately dug into the supplies duffle, pulling out a camping lantern.

"Of course," Optimus said with a shake of his head, and left the cabin again. As a laughing Ironhide informed him, deadwood was fair game for firewood, and Optimus searched carefully for about twenty minutes before finding a suitably dead tree - still standing - and carefully breaking it down into suitable pieces. And then doing so again once he got back to the cabin, transformed to his smaller size, and realized his size perception was still a little off. There was a decent pile of wood right outside the cabin now though, and he headed inside the now brightly-lit cabin to find Alex sitting on the cooler, calmly eating from a small tub of ice cream, a bottle of sparkling wine sitting on the floor next to her feet.

"Don't look at me like that, it was all the camping store had," Alex said defensively as she lifted the bottle to drink directly from it.

"Ice cream?" Optimus asked instead, smiling faintly as he headed for the fireplace.

"Shut it, tiny," Alex ordered sternly after taking a drink of the wine, then nodded to the fireplace. "I'm assuming you still have a net connection out here, which means you have more of an idea of how to start that thing than I do."

"On second thought, perhaps insisting on being the first test subject for mass-shifting transformation tech was not the best idea," Optimus said thoughtfully. "You ordered me around more than enough _before_ I was the same size at you."

"Hah. Too late," Alex said, sticking her tongue out at him. "Besides, everyone orders you around when no one else is looking, and you let them. So it's your own fault."

"How would you know that, if no one else is looking?" Optimus asked dryly.

"I hear stories," Alex replied primly.

"Right, of course," the Prime said, grinning as he finished arranging the wood in what he thought was a suitable way before shifting some components around to produce a shower of sparks. One or two caught, quickly growing into flames, and he nodded in satisfaction, standing and stepping back.

"Alien robots officially make campfires better than me, even without laser guns," Alex said cheerfully, coming to join him by the fire, small tub of ice cream still in one hand.

"The internet is very helpful," Optimus said matter-of-factly.

"YouTube?"

"Better than Iacon's library." They looked at each other, grinning. Optimus broke it with a chuckle, and Alex snickered softly before going to drag the cooler over. She rearranged the camping lanterns she'd put up around the cabin, then moved the heaviest piece of firewood, which Optimus had been intending to break down, in front of the door. Optimus didn't comment, letting her set things up as she wanted, helping where he was needed. This was, after all, exactly why they were up here. New transformations could take a little getting used to, and that was when you remained the same size. This was...extremely disconcerting, especially when Alex asked him to get something out of one of the duffels, which was zipped. Before, there was no way he would have been able to open a zipper - it was simply too small. Now, he was the right size to operate the simple mechanism, and he spent a few moments staring at his hands on the zipper before shaking himself and getting back to it.

Eventually, Alex had a little nest set up close to the fireplace and its roaring fire - not close enough to let anything catch fire, but enough to take advantage of its warmth. The cooler and duffel bags formed a back wall to the nest, and Alex kicked off her shoes to put beside her before settling with a sigh. Her ice cream was long finished, but the wine was only half gone and now sat within arm's reach as she looked up to Optimus.

"Alright Prime - have a seat and start explaining," she said easily, clearly more at ease now. Optimus tentatively sat next to her, the action feeling entirely new with his altered size and center of gravity, and took a few moments to find a position that was comfortable on the sleeping bag Alex had spread out before speaking.

"Which 'why' would you like me to start with?" he asked.

"Why have you guys been trying to make yourselves small for forever?" she prompted.

"As a species, we're on the large size of civilized races in the galaxy. It makes things inconvenient when dealing with other races," Optimus replied easily. "Granted, we can rebuild ourselves down into mechs of Jazz's size or even smaller for convenience, but that would be akin to eliminating racism on your planet by altering every human's skin to be one colour."

"We can't actually do that, you know," Alex said with a laugh.

"No, but if you could," Optimus supplied. "Size is a personal choice for us, part of who we are. Jazz doesn't just prefer to be small because it's useful, he simply _is_ small. That it helps him do his job is just a side-effect."

"Alright. So not all of you want to be small. And yet..." Alex looked the Prime up and down, arching an eyebrow.

"Transformation is another matter entirely," Optimus said with a chuckle. "We have no problems with changing into vehicles that fit in more easily on whatever planet we're on, why should size make a difference to that? So long as it's not a permanent rebuild, that is."

"Sounds like a fine distinction you'd need to be Cybertronian to fully appreciate," Alex said dryly.

"Probably," Optimus agreed, smiling warmly at his charge, able to tell that she understood - or at least accepted - what he'd been saying.

"Alright. So you guys have been trying to be temporarily small for awhile now to fit in better. How? Why now? Why did you volunteer?" Alex asked.

"The simple answer first - I volunteered because it's an experimental technology and it was either me or Wheeljack, and I'd rather have him around to fix me if it all somehow goes horribly wrong. Also, Ironhide refused to risk Annabelle's safety on even the smallest chance that the technology might fail. Which, as it happens, is less than 0.05%." Optimus gave his charge a reassuring smile.

"I'm not sure I want to contemplate what you mean by 'fail'," Alex said with a shake of her head. "And the rest?"

"You'd have to asked Wheeljack and Ratchet for the details of how, but the basics as I understand it are that the advances in space bridge technology, and the technology Starscream invented than allows Megatron's fusion cannon to be quantum-linked to a black hole, gave them enough understanding of the way the universe works that they're now able to create something called a subspace pocket. In the long run, they say they should be able to equip everyone with these pockets, allowing for unknown amounts of personal storage without needing to carry anything on oneself. For now, however, they've linked a subspace pocket up to my spark chamber and transformation processors, allowing me to shift most of my mass into that subspace pocket, keeping it in suspended animation while I keep only the parts required for this much smaller frame."

"So this frame actually functions completely independently, and isn't just a facsimile that's being run by all your subspaced mass?" Alex asked with actual curiosity, and Optimus gave her a surprised look as she asked a question he would have expected more from Mikaela or one of the NEST scientists.

"So far as I understand it, yes," the Prime said, his own interest at Alex's curiosity rising.

"I'm gonna be completely socially unacceptable here and ask if I can have a look under your armor to see," she said, a teasing grin on her face that said she expected him to laugh it off and refuse.

"If you want," Optimus said amiably instead, loosening the locks on his armor with an audible click. Alex blinked at him.

"Seriously?"

"As you keep telling me, you've seen it all before anyways," he told her dryly, and Alex laughed before pushing herself up and leaning forward, pulling up one of his shoulder plates. She set it back down again quickly enough, but then continued investigating, down his arm and across his abdomen, even peeking up under his chest plates, though she didn't lift them. She gave a running commentary as she went, mostly along the lines of "hey that's cool!", with the occasional "that used to be over there!" Optimus made a mental note to speak to Ratchet and Wheeljack about training her the same way they were training Mikaela. He hadn't though Alex was interested into anything other than trucking, but now it occurred to him that she'd never really had the opportunity to do anything else, and might not even think she had the option. She certainly seemed to have an interest in Cybertronian physiology, however, and that was something worth encouraging.

"Alright, done being rude now," Alex finally said, grinning up at Optimus as she settled back on the sleeping bag. He engaged his armor locks again with a chuckle.

"Hardly rude. I had no idea you'd be interested, or I would have asked Ratchet about letting you observe the installation," he said.

"Nah, subspace pockets and sparks flying around? Doubt it would have been safe for fleshy ol' me," Alex said easily, laying back, hands behind her head as she closed her eyes. "Though I am curious as to why you get this fancy new tech, then come all the way up here to try it out. I would have thought you'd have wanted to stress test it with Will and the rangers or something."

"Ah, well, we're not entirely sure if we want to let on to the government that we have it right now," Optimus said with a sigh. "Wheeljack's still working on the adaptation, but given time, he could make hologram projectors that fit with these smaller forms, allowing us to pass for human at a distance."

"Oh. Yes, I can see why," Alex said with a frown, opening her eyes to consider the Prime.

"It's unlikely many of us would use such a capability, of course, but the possibility is bound to worry some," Optimus mused. "Especially if the Decepticons realized that capability and used it to instigate new hostilities."

"True, true. So this is the safest place to stress test it, then?"

"Precisely. We had considered the Lennox's property, but as mentioned, Ironhide was concerned about Annabelle's safety," Optimus said with a smile and a shake of his head.

"Should I be concerned for mine?" Alex asked in a drawl.

"Ironhide heard that the technology behind Megatron's fusion cannon helped make it possible and stopped listening to safety reassurances, especially since they came from Wheeljack," Optimus replied with a chuckle, and Alex grinned, but arched an eyebrow at him. "No, you shouldn't be concerned. Ratchet wouldn't have let me travel one minute away, let alone half a day, if he thought the technology might fail catastrophically."

"Only catastrophically?" Alex asked with a laugh.

"So far as Ratchet and Wheeljack are both concerned, they've put so many fail safes into this technology that the worst thing that can happen is that I'll have to run outside in a hurry or spontaneously return to my normal size inside the cabin. And they assure me I'll have at least 30 seconds of warning alarms blaring at me before that happens," Optimus informed her with a laugh of his own.

"Well, good!" Alex returned, her eyes slipping closed again. One immediately popped open again to look at him. "You can recharge like this, right?"

"Completely normal functionality, barring combat capabilities."

"Good. Cuz if I wake up alone in a cabin in the middle of buttfuck nowhere, I _may_ just have an emotional breakdown," Alex said, eyes closing again.

"Why _are_ you so terrified, anyways?"

"Ask Cliffjumper. I'm gonna catch some sleep and _not_ think about it."

"Very well. Did you want me to move or turn down the lights?"

"Nah, I'm good. Fire's warm, you hum, and it's too dark out here anyways."

"...too _dark_?"

"Shut up, space alien. Sleepin'." Optimus let out a quiet chuckle, but fell quiet, allowing Alex to sleep as he opened a comm line to Cliffjumper. Which was how he was introduced to the horror genre of human movies. When he murmured a sincere and sparkfelt apology to Alex later, shifting close and feeling just the tiniest bit more protective, she smiled sleepily and patted his arm before falling back asleep.

\---

Optimus woke with dawn, intending to restart the fire and turn out the camping lanterns for Alex before getting in some morning meditations. His recharge was...different in such a small form, with so many of his more powerful processors offline and subspaced, but it wasn't unpleasant. More relaxing, even. He was also, he discovered, more oblivious to his surroundings than he'd thought. Nothing bad had happened, however he woke to Alex draped half over him, head well off her pillow as she breathed softly near his audio.

Optimus turned his head carefully, found himself almost nose-to-nose with his charge, and was suddenly reminded of the more...ribald reasons for implementing this technology that Jazz had joked about. Or possibly not joked - it _was_ Jazz. And maybe Optimus as well, the Prime admitted to himself, there on the quiet Wyoming mountain morning as Alex snuggled up against him, peaceful and relaxed despite her fear the night before. Tentatively lifting the hand Alex wasn't laying on, Optimus reached over, hesitated a moment, then lifted some of the hair that was draped over her face. He marveled momentarily at having the manual dexterity and size now to be able to actually grasp strands of her hair without disaster ensuing, and he found himself unable to resist moving more of her hair away from her face, brushing it behind her ear before finding himself fascinating by the rigidity and flexibility of said ear.

He was distracted enough that he didn't realize at first that Alex had woken up, until he glanced down and realized she was watching him quietly. He went to make a joke, about returning the favour in the socially inappropriate anatomy inspection, but it wouldn't come out. Instead he just found himself staring back at her, his hand leaving her ear to rest along the plane of her neck, so smooth and different from that of a Cybertronian's. They were close enough that the eventual movement from Optimus wasn't much, the barest twitch forward, but it was enough to indicate intent, and he was beyond shocked when instead of pulling away, Alex returned it, closing the remaining gap in the wholly alien gesture of a kiss.

The new, mobile faceplate on this smaller form had not only giving Optimus a more human face, but actual soft 'lips'. There was little feeling in them, of course, but underneath were pressure sensors that did well enough, and his mouth had chemoreceptors, especially on the glossa, which Alex didn't seem to mind making its way into the kiss at all. Optimus decided he quite liked it too, the previously incomprehensible idea of 'locking lips' with someone suddenly making _sense_ now that he was experiencing it. There was some unquantifiable type of intimacy to the gesture, that words not only weren't needed, but would legitimately get in the way of the whole thing.

It couldn't last forever though, Alex eventually pulling back, her breathing much heavier now, though her eyes were closed. When she opened them, there was a spark of the fearless determination Optimus had grown to appreciate in her staring up at him, her smile steady.

"Good morning," she said, quietly.

"Good morning," Optimus replied with a smile of his own.

"We chalking that up to the whole stress testing the upgrade thing?" she asked, smile going lop-sided as she arched a brow. Optimus considered - it was another easy out, as his intended joke earlier would have been. As many of his Autobots, and even Megatron, had cursed at him for though, Optimus rarely did things the easy way.

"We could if you'd like," he responded amiably, then ducked in to hover right by her lips again. "Definitely not this one, though." He kissed her again. Alex responded readily, her free hand coming up to clutch at Optimus's shoulder, and he shifted, maneuvering more onto his side so that he was facing her instead of her laying half on-top of him. Alex accommodated, pressing closer, and Optimus ran his hand down her neck to her side, coming to a rest on her waist. It took him a moment to realize that her sucked in breath was from his hand resting on bare flesh instead of her shirt, which had hiked up during the night, and he dialed up the sensitivity of his tactile sensors - and oh, that had been a really good idea, now the kiss was even better.

So was Alex's hand on his armor - or rather, under his armor. She definitely knew more than she was letting on about Cybertronian physiology, Optimus realized, as her fingers dipped into seems to the sensitive pieces, starting up a charge that Optimus hadn't indulged in since before landing on Earth. He wasn't about to stop this now, however, and let it build, his own hand pushing up under her shirt, caressing skin that he'd rarely seen before. Alex arched into his touch, a quiet moan escaping into the kiss, and Optimus rolled onto his back, tugging her on top of him. It occurred to Optimus after the movement was already done that with his smaller size he didn't necessarily have to be the one on the bottom - there were disadvantages to being one of the larger mechs out there sometimes.

Alex certainly didn't seem to mind the new position though, straddling him easily as she continued the kiss, her fingers finding their way under that armor she'd peeked under the night before, while he pushed her hiked-up shirt even higher, to the point that she pulled back and just removed it entirely. Optimus gave her torso a curious look, but his gaze was more focused on the one thing she still wore on her top half, which he'd never actually seen before, though he'd caught a few conversations from time to time. Alex glanced down at her bra, then with a half shrug, reached behind her back and removed it too. She ducked back down for another kiss, and Optimus couldn't quite stopped a full-body shudder at the sensation of her bare torso pressed against his armor. Alex pulled back a fraction, giving him a curious look.

"No?"

"Good shudder," Optimus informed her, his voice rough, and he arched an optic ridge as he felt Alex shiver in turn.

"Shut up," she told him sourly, then leaned down by his audio as her hand ran down the cables in his neck in a way that shouldn't have been sensual but was. "Keep talking," she murmured, and Optimus let out a brief laugh as he ran his hands down her bare back. He was, after all, well aware of how attractive most people considered his voice to be. Especially humans, since only a few of them really seemed to understand the range of Cybertronian hearing (Optimus was fairly sure Epps was one of the few that knew and had been trying to make him just as uncomfortable as he'd managed to make the new NEST recruits with that comment)(Optimus had, of course, not been embarrassed in the slightest).

"I'm not really sure there are appropriate words for right now," Optimus said, right into her ear. "Especially since I've finally discovered the draw you humans having for kissing." He caught her lips in another kiss then, and Alex's response was more ardent than it had been before as she pressed against him. Her reach under his armor was limited, though, and she couldn't return the charge he was building like another Cybertronian could, so on a whim, Optimus undid the locks on his armor again. And it really shouldn't have been as erotic as it was to have her entire hand slip up under an armor panel and caress the cables underneath, but that's where all the sensors were anyways, so he supposed it made sense. Not that sense had much of anything to do with this right now. Still, there was perhaps...some sense that needed to be retained, Optimus realized with a groan as Alex hit a particularly sensitive node of sensors.

"Just - ah - how much do you know about Cybertronian physiology, anyways?" he asked, pulling back from the kiss. Alex was kissing along his new jaw, and wiggled her hips a little, making Optimus groan again and try not to buck up against her as she moved across a _very_ sensitive panel.

"That answer your question?" Alex purred in his audio, her hips pressing down. "Just please for the love of Primus tell me someone, I'm going to assume Jazz, was perverted enough to bribe Ratchet into making sure there's no biological incompatibilities there."

"Someone was, and there isn't," Optimus agreed, his voice a low growl now as he gripped Alex's hips, pressing her close even as he ground upwards.

"Shit, ah - watch the grip," Alex moaned, and though there was no pain in her tone, Optimus immediately loosened his hold on her hips.

"Sorry," he murmured in her ear.

"S'ok, hardly be the first time I get bruises there for that reason," she told him with a mischievous grin.

"I could do a fair bit more than just leave bruises," Optimus said, embarrassment flushing some of the charge from his systems.

"You wouldn't, though. Especially not now," Alex replied easily, smiling at him, her hand coming to rest on his chest plates for a moment before she kissed him again. She started caressing and tweaking cables and sensors again, and Optimus had to marvel just a little at her trust. It was one thing for a smaller Cybertronian to trust him not to hurt them - their substructures were ultimately made of the same material, and there was only so much damage he could do, unintentionally or not. She was flesh and _bone_ , though - he could easily pulverize both, even in this smaller form. Optimus turned away from that line of thinking, concentrating instead on caressing her. Her body was arched up a little at the moment, and he realized it gave him access to the fastening for her pants. He undid them with relative ease, which seemed to surprised Alex, but then she rolled part-way off of him and started wriggling out of them entirely.

She was back quickly, completely bare now, and Optimus found himself glad that certain of his Autobots were as 'perverted' as Alex had just accused them of being, because he felt somewhat confident in the way things were going as she pressed down against that same heated panel. This was nothing like what interfacing with another Cybertronian would be like at this point, of course, and Optimus realized relatively quickly that the panel probably wasn't going to open on its own, so he overrode it. The quiet _snikt_ of the panel retracting sent a shiver through Alex, goosebumps raising on her arms, but it was just as quickly dismissed with a breathy laugh, and she nipped at a cable in Optimus's neck. Optimus kissed the part of her ear that he could reach, and that seemed to remind her of his own audios, the filials attached to them, and all the jokes made about how sensitive they were. He let out a hiss of pleasure as she ran her tongue over the edge of the closest filial, and his concerns about having trouble pressurizing his spike after needing to override the panel disappeared like that.

Alex's breath hitched as she felt is spike against the inside of her thigh, and she drew back, glancing down briefly before evidently deciding she saw nothing concerning and resuming her attention to his filial. Optimus moaned, not embarrassed in the least to let her know that she'd found his sweet spot, and she caught the cue, thoroughly molesting both filials until he had to pull her hands away before he lost all coherency. Alex let out a small laugh, but that quickly turned into a breathy moan as he maneuvered his spike to her entrance and in one smooth motion, slid in. He didn't move immediately afterwards, and she gave him a slightly confused look after a moment.

"Oh. Right," Optimus said with a chuckle. "Large size differences among our species means we have, ah, adaptive equipment."

"Adaptive equi- oh." Alex blinked, and Optimus smirked faintly before _adapting_ a little, to a slightly larger size - not a way he was used to going, but still capable of, and it seemed humans were more flexible than Cybertronians of a corresponding size. "Oh holy _shit_ that's weird and amazing," Alex gasped out.

"Normally there would be physiological feedback, however I'm going to need to rely on verbal here," Optimus said, smiling as he kissed her neck.

"Uhn?"

"More? Or less?"

"Ah, fuck, bit more," Alex said, and Optimus obliged. "Can you adapt length?"

"Of course."

"Longer then."

"How's that?"

"Perfect. Weirdest feedback I've ever given during sex," Alex said, but then shifted her hips, and it was Optimus's turn to gasp. The Cybertronian standard was very little movement once a spike was in - most of the stimulation was internal, done by the receiving valve. Humans didn't have the same extent of control, of course, so Alex started moving, and Optimus found that while it was different, it did the job just well. His charge built up again, past where it had been before, and he realized he was starting to give off little electric shocks. At first he was concerned that they might be powerful enough to hurt Alex, but her shudders at each one seemed to be of pleasure, not pain, so he didn't stop touching her, letting his overload flow out through his armor as usual as he came with a deep moan. He felt Alex cum above him, the signs the same in human or Cybertronian, body tensing, quivering with pleasure, and he made his optics focus on her, made sure he saw her face, lost in pleasure.

When she came down from her orgasm, she had an easy, open smile on her face, which she directed to Optimus. He smiled back at her, and she leaned down to give him a long, lazy kiss.

 _"Ratchet to Alex and Optimus. Any glitches overnight?"_ Optimus cut the connection for both of them, since Ratchet was routing through his comms to reach Alex out here anyways, with a brief tone that was the Cybertronian equivalent of a curt "we're busy, go away," and Alex pulled away from the kiss with a burst of laughter.

"That's only going to either worry or piss him off," she said with a giggle, collapsing onto her side beside Optimus.

"If I'd gotten around to them, I wouldn't even be done my meditations by now, and he knows it," Optimus retorted with a laugh.

"Maybe he knows you didn't get around to them?" Alex said, wiggling her eyebrows, and Optimus laughed again, leaning over to give her a quick kiss.

"I very much doubt that - _I_ wasn't even consciously considering this until this morning," he said.

"That's ok, Beth and Jumper had it covered for you," Alex drawled.

"What?" Optimus asked, frowning.

"Seriously?" Alex asked, arching an eyebrow. "How have you not heard of that?"

"Heard of what?"

"They've been convinced for years that whenever I'm home and go out to chat with you at night, we're actually having sex," Alex drawled. "Pretty sure they're convinced we do it all the time on the road, too."

"For Primus's sake..." Optimus said with slight exasperation, but immediately chuckled before ducking his head to speak right into Alex's ear. "We can now if you want."

"Horny robot," Alex teased, smacking his armor, which rattled more than it should have. Optimus let out a small, embarrassed buzz of static and engaged his armor locks again, which made Alex collapse into giggles. "Millions of years of war and you forget to relock your armor after sex with me?"

"It was very good," Optimus said companionably, and Alex blushed a little, grinning widely.

"Glad you think so," she said.

"Mmm, I do. May I assume it wasn't entirely terrible for you, either?" Optimus said, nuzzling at her neck.

"S'alright," Alex said casually, shrugging lightly, and Optimus pinched her hip lightly. Alex giggled. "'Adaptive equipment' - best surprise ever in the middle of sex." Optimus chuckled again.

**\- END -**


End file.
